Orthodontic devices for use with arch wires

ABSTRACT

An orthodontic bracket or convertible buccal tube for use with arch wires has the usual mesial distal extending slot having one side open to receive the wire. The open side is closed by a shutter pivoting on a pivot pin, or coaxial pins, about a mesial distal axis, the shutter being latched in slot closed position to retain the arch wire by a latch having one latch member on the pivot pin/s and a cooperating member on an annular part of the shutter surrounding the pin/s. Preferably the latch members are a mesial distal extending cam shaped recess in the pivot pin/s and a projection protruding from the annular shutter part, or vice versa. The part of the annular shutter part carrying the latch member is made flexible by a mesial distal extending through slot dividing it to form a movable segment of about 200° to 270° of the total circumference; a tool can be inserted into the slot to assist in disengaging the latch. The shutter member can have parts thereof that with the shutter in slot closed position are an interference fit against the device body providing an additional retaining force against opening movement. Preferably the device includes an attitude controlling spring member consisting of a thin sheet metal spring within the body having a free end extending into the arch wire slot to engage an arch wire therein, or alternatively consisting of a flexible extension of the part of the shutter member that closes the slot.

CROSS REFERENCE TO A RELATED APPLICATION

This application is a continuation-in-part to my prior application Ser.No. 10/623,528, filed 22 Jul., 2003, the priority of which is claimedunder 35USC120 and which is abandoned upon filing of this application.

FIELD OF THE INVENTION

This invention is concerned with improvements in or relating toorthodontic devices consisting of orthodontic brackets and convertibletype tubes that are used in orthodontic procedures in cooperation witharch wires, and particularly such devices which have arch wire attitudecontrolling spring means as a permanent part thereof.

BACKGROUND OF THE INVENTION

Orthodontic procedures almost always employ a plurality of orthodonticbrackets that are attached to respective teeth, usually by cementingthem thereto, although in some circumstances the bracket may still beattached to a metal band which embraces the tooth. Each bracket has amesial distal extending slot therein, usually of rectangular crosssection in a gingival occlusal plane, and the brackets are connectedtogether using an arch wire, so called because it is preformed to anoptimum arch shape corresponding to the desired conformation of theteeth at the conclusion of the procedure. In the so-called labialprocedures, which are the most commonly employed, the brackets areattached to the labial surfaces of the teeth and the slots open towardthe labial for insertion and removal of the wire, which is retained inthe slots by ligating means of some kind. In “lingual” procedures, whichhave the advantage that the brackets and the wire are usually concealedfrom frontal view, the brackets are attached to the lingual teethsurfaces and the slots open toward the lingual or occlusal. Arch wiresof progressively increasing stiffness and, depending on the type oftooth movement to be achieved, also of different cross sections, areused one at a time. Historically, when first employed the brackets were“passive”, in that ligation of the arch wire to the bracket to obtainthe necessary action between them was external to the bracket, at firstconsisting of a soft metal wire twisted around them, while increasinglyan elastomeric hoop or loop is used in place of wire.

The ends of the arch wire may be engaged in terminal tubes, usuallyattached to the molars so as to anchor the arch wire firmly in place.Tubes may also be employed on intermediate teeth in place of bracketswhenever this is appropriate. In its simplest form a terminal orintermediate tube is passive and consists of a short piece of tubeattached to a base by which it is mounted on the tooth surface, the tubebore opening at least mesially so that the arch wire end must beinserted therein. This is not always convenient, and may not be possiblewhen the tube is on an intermediate tooth, and the solution is then touse a tube of the so-called convertible type, with which one side of thetube bore can be opened when required for insertion of the wire therein,or its removal. It is also possible to incorporate in such a tube anarch wire engaging attitude controlling spring member that will urge thewire into contact with two of the slot walls, whereupon the tube isactive as well as convertible. It will be apparent from the foregoingbrief description that there can be considerable overlap between thefunction and appearance of brackets and tubes, with the result that itmay be possible for a particular orthodontic device to be considered bysome orthodontists as a bracket, while others will think of it as atube. In general, a device in which its body is noticeably bigger ingingival-occlusal dimension than mesially-distally will usually beregarded by most practitioners as a bracket, while one in which theopposite is the case will be regarded as a tube.

The term “orthodontic devices” as used herein, in both the specificdescription and in the claims, is intended therefore to include bothbrackets and convertible tubes within its scope. The adjective “buccal”commonly is used to indicate that a device is on teeth that are facingthe cheeks, while “palatal” or “lingual” are used to indicate that adevice is facing the palate and the tongue. More specifically palatal isused in referring to the “inward” facing surfaces of the upper bicuspidsand molars, but increasingly lingual is used for all teeth, while labialis used to refer to the upper and lower canines and incisors, and buccalis used to refer to the upper and lower bicuspids and molars.

Brackets as used in the Hanson SPEED System (Trade Mark) are “active”,sometimes referred to as “self-ligating”, in that each comprises apermanent ligating spring member which embraces the bracket body and ismoved thereon between slot open and slot closed positions, the springmember performing the dual functions of retaining the arch wire in theslot, and also urging it to an optimum position within the slot.Specific examples of such active brackets are disclosed and claimed inmy U.S. Pat. Nos. 4,248,588 and 4,492,573.

In another line of development the orthodontic device is provided with ashutter which is movable between slot open and closed positions, in slotclosed position retaining the arch wire in the slot. The shutter alsofunctions, at least initially, by its engagement with the wire to urgethe device and the arch wire to their optimum or neutral positionrelative to one another, at which position the constraint between themis minimized. Since in at least the initial stages of the procedure thearch wire will usually be of cross section smaller than the slot, such adevice preferably is provided with an internal attitude controllingspring that protrudes into the slot to engage the wire and provide adesired controlling force. Such a shutter can be of thicker materialthan an embracing ligating spring and less flexible, so that it can moreeasily be made much less sensitive to overstressing beyond the elasticlimit of the material, while still being sufficiently flexible for it tobe held securely in slot closed position by its jamming engagement withthe device body while under the onerous conditions encountered inpatients' mouths during typical orthodontic procedures. Examples ofdevices consisting of such brackets and convertible tubes are describedand claimed in my U.S. Pat. No. 6,506,049, issued 14 Jan., 2003, thedisclosure of which is incorporated herein by this reference.

There is a constant endeavor to provide devices that are as small andwith as smooth an exterior as possible, for cosmetic reasons to pleasethe patient, in order to reduce as much as possible any rough contactbetween the tongue, the devices and the adjacent mouth tissue with itsconsequent discomfort, and for hygienic reasons to reduce the number ofareas in which food and dental plaque can accumulate. It is of interestto both orthodontists and patients to provide devices that interfere aslittle as possible with speech. The orthodontist is interested inaddition to use devices that while low in cost provide fast, precise andeffective movement and attitude control of the teeth.

There is increasing interest in the lingual technique, even though suchprocedures are more difficult to implement. A compromise is to use thelingual technique only for the upper arch, where the brackets and archwire would otherwise be most visible, and the labial technique for thelower arch, where the brackets and arch wire are mostly hidden by thelower lip. Lingual and mixed lingual/labial procedures are of specialinterest to adult patients who are more concerned than children withappearance during the two to three year period required for a typicalprocedure. The compromise is not so suitable for older patients who tendto show their lower teeth more, and in some cases primarily displaytheir lower anterior teeth. Small smooth devices are needed particularlyfor the lingual location because of ready access by the tongue, and thenatural tendency for the tongue to explore any foreign object in themouth. Attempts simply to reduce the size of existing devices are notgenerally successful, at least partly because changes in scale affectssize parameters in different ratios, e.g. areas decrease in square ratiowhile volumes decrease in cube ratio, with the result that it becomesincreasingly difficult, especially with the tiny spring membersrequired, to find materials of the necessary properties. Examples ofsuch small, smooth exterior brackets suitable for lingual procedures arethose described and claimed in my U.S. Pat. Nos. 4,698,017 and5,685,711, issued respectively 06 Oct. 1987 and 11 Nov. 1997

The manufacture of orthodontic devices and equipment is now a matureindustry, and there is an ongoing requirement to provide devices thatare efficient, economical and easy to use. Increasingly there is theadded requirement for them to be as inexpensive as possible, especiallyif orthodontists are to be persuaded to make the changes in theprocedures in which they were trained, and with which they are veryfamiliar, and that the adoption of any new device usually entails.

SUMMARY OF THE INVENTION

It is a principal object of the invention therefore to provide neworthodontic devices, and particularly those which are of the typecomprising a permanent attitude controlling metal spring that can engagean arch wire in the arch wire receiving slot.

It is another principal object to provide new devices of small size andof an exterior shape that makes them specially suitable for use inlingual techniques, particularly in association with incisor or canineteeth.

In accordance with the invention there is provided an orthodontic devicefor use with orthodontic arch wires comprising:

-   -   a device body having labial, lingual, gingival, occlusal, mesial        and distal surface portions, the body having therein a        mesial-distal extending arch wire receiving slot having one        mesial-distal extending side open to a device body surface        portion to permit insertion of an arch wire into the slot and        its removal therefrom;    -   a pivot member mounted by the device body and establishing a        mesial-distal extending pivot axis; and    -   a shutter member mounted by the pivot member for pivoting        movement about the pivot axis between a slot open position in        which the open slot side is open, and a slot closed position in        which the shutter member closes the open slot side to retain an        orthodontic arch wire in the slot;    -   wherein the shutter member comprises:        -   a pivot portion mounted by the pivot member for the pivoting            movement of the shutter member;        -   a slot closure portion movable with the pivot portion,            extending mesially distally with respect to the device body,            and in the slot closure position closing the slot open side;            and        -   latch means having latch means members cooperating with one            another and operative between the pivot member and the pivot            portion when the shutter member is in slot closed position            to retain the shutter member in that position.

The cooperating latch means members may comprise a recess in one of thepivot member and the pivot portion, and a projection from the other ofthe pivot member and the pivot portion, wherein with the shutter memberin the slot closed position the recess and projection are cooperativelyengaged with one another to retain the shutter member in that position.Preferably the recess is provided in the pivot member and the projectionis provided on the pivot portion.

The shutter member pivot portion may comprise a pivot portion partembracing the pivot member, the pivot portion part having a mesialdistal extending bore therein through which the pivot member extends sothat the pivot portion part has a wall of at least approximately annulartransverse cross section around the pivot member;

-   -   the wall having therein a mesial distal extending radial slot        from its interior to its exterior so that the wall is        discontinuous around the pivot member and has a movable segment        thereof able to move radially toward and away from the pivot        member by flexing thereof; and    -   wherein one of the latch means members is carried by the movable        segment and moves into and out of engagement with the other of        the latch means members by the flexing of the movable segment.

The movable segment may constitute from about 200° to 270° of the totalcircumference of the pivot portion part wall with the respective latchmeans member disposed immediately adjacent to the radial slot. Themovable segment may have a part thereof adjacent to the respective latchmeans member extending radially outward and engageable with a surface ofthe device body to limit the movement of the shutter member beyond adesired slot open position.

The radial slot in the pivot portion wall may have a tool receivingaperture therein through which a tool is inserted by an operator forflexing of the movable segment to disengage the latch means for movementof the shutter member out of the slot closed position.

The pivot member may comprise a single pivot pin and the tool receivingaperture is continued into the pin to permit adequate insertion of thetool into the aperture, or instead the pivot member may comprise twoseparate coaxial pins having their facing ends spaced apart to permitinsertion of the tool between them.

In the slot closed position of the shutter member the mesial and distalends of the slot closure portion may engage with immediately adjacentsurface portions of the device body with an interference fit engagementbetween them providing a retaining force in addition to that provided bythe latch means so that the shutter member is also constrained therebyin the slot closed position against movement out of that position, andmovement of the shutter member into the slot closed position requiresflexing of the slot closure portion in a direction away from the devicebody against the resilience of the material of the slot closure portion.

There may be provided in a recess within the device body an attitudecontrolling spring member having a fixed end portion fixed againstmovement relative to the device body and a free end portion extendinginto the arch wire receiving slot for engagement in a mesially-distallyextending plane with an arch wire in the slot. The attitude controllingspring member may be of thin metal sheet with transversely extendingside arms, and may be retained within the device body by having the sidearms sandwiched between a part of the device body containing the archwire slot and a base member fastened to the device body.

Alternatively an attitude controlling spring member may be constitutedby a flexible extension of the shutter member that with the shuttermember in slot closed position has a free end portion extending into thearch wire receiving slot for engagement in a mesial-distal extendingplane with an arch wire in the slot, such engagement urging the archwire into engagement with the respective slot walls. Preferably, in theslot closed position the flexible portion of the shutter member ispositively engaged with a surface of the device body so as preload theflexible portion and urge the free end portion toward engagement with anarch wire in the arch wire slot.

With a device particularly intended for application to the lingualsurface of an incisor or canine tooth, which teeth are characterized inthat their labial-lingual dimension decreases progressively from thegingival to the occlusal; and

-   -   wherein in the slot closed position the occlusal surface portion        of the shutter member is flush with the occlusal surface portion        of the device body to thereby provide a combined occlusal        surface which is unobstructed;    -   the gingival-occlusal dimension of the device body may decrease        progressively from the lingual to the labial, the decrease        corresponding to the average increase from the occlusal to the        gingival of an incisor or canine tooth, so that when the bracket        is attached to the lingual surface of an incisor or canine tooth        the unobstructed combined occlusal surface provides a        labial-lingual extending bite plane surface which a tooth edge        of an opposed incisor or canine tooth can engage during biting        action to oppose overbite.

Also in accordance with the invention there is provided an orthodonticdevice for use with orthodontic arch wires comprising:

-   -   a device body having labial, lingual, gingival, occlusal, mesial        and distal surface portions, the body having therein a        mesial-distal extending arch wire receiving slot having one        mesial-distal extending side open to a device body surface        portion to permit insertion of an arch wire into the slot and        its removal therefrom;    -   a pivot member mounted by the device body and establishing a        mesial-distal extending pivot axis; and    -   a shutter member mounted by the pivot member for pivoting        movement about the pivot axis between a slot open position in        which the open slot side is open, and a slot closed position in        which the shutter member closes the open slot side to retain an        orthodontic arch wire in the slot;    -   wherein the shutter member comprises:        -   a pivot portion mounted by the pivot member for the pivoting            movement of the shutter member;        -   a slot closure portion movable with the pivot portion,            extending mesially distally with respect to the device body,            and in the slot closure position closing the slot open side;            and        -   an attitude controlling spring member constituted by a            flexible portion of the slot closure portion that with the            shutter member in slot closed position has a free end            portion extending into the arch wire receiving slot for            engagement in a mesial-distal extending plane with an arch            wire in the slot, such engagement urging the arch wire into            engagement with the respective slot walls.

DESCRIPTION OF THE DRAWINGS

Orthodontic devices that are particular preferred embodiments of theinvention will now be described, by way of example with reference to theaccompanying diagrammatic drawings wherein:

FIG. 1 is a perspective view from the mesial-occlusal of a firstembodiment with its pivoting shutter member in slot closed position;

FIG. 2 is an exploded view from the same perspective as FIG. 1 of thefirst embodiment;

FIG. 3 is a longitudinal cross section in a central labial-lingual planethrough a second embodiment with its shutter member in slot closedposition;

FIG. 4 is the same cross section as FIG. 3 of the second embodiment withthe shutter member in slot open position;

FIG. 5 is a perspective view similar to FIG. 1 of a further embodiment;

FIG. 6 is a perspective view from the same perspective as FIG. 5, butshowing only the shutter member of the embodiment of FIG. 5;

FIG. 7 is a side elevation from the mesial of a further embodiment thatemploys a shutter member of the same configuration as that in FIG. 6,and showing the start of jamming cooperation between the shutter memberand the bracket body during movement of the shutter member toward slotclosed position, such cooperation assisting in retaining the shuttermember in that position;

FIG. 8 (Sheet 1) is a perspective view showing brackets as shown in FIG.5 attached to the lingual surfaces of incisor teeth, and showing also atool suitable for moving the shutter member to slot open position;

FIG. 9 is a side elevation from the mesial showing a bracket of theinvention in solid lines, and one of my prior art brackets in brokenlines, the outlines of the brackets being superimposed upon one anotherso as to provide a comparison of their sizes;

FIGS. 10 and 11 (sheet 6) are central longitudinal cross sectionssimilar to FIGS. 3 and 4 of a further embodiment, in which the shuttermember is positioned toward the lingual end of the bracket body, insteadof toward the labial end;

FIG. 12 (Sheet 5) is a central longitudinal cross section similar toFIGS. 10 and 11 of a further embodiment in which the placement ofcooperating latch means members is reversed as compared with the otherembodiments previously shown and described herein;

FIG. 13 (Sheet 5) is a central longitudinal cross section of a furtherembodiment, taken on the line 13-13 in FIG. 12, and showing one way inwhich the bracket can be provided with hooks for engagement withsupplementary orthodontic devices;

FIG. 14 is a view toward the labial of the embodiment of FIG. 13;

FIG. 15 (sheet 9) is a perspective view from the mesial/lingual of abracket in which a pivot member pin extends mesially and distally beyondthe bracket mesial and distal surfaces to provide anchoring means forauxiliary devices;

FIG. 16 is a central longitudinal cross section of a further embodimentprovided with a mesial distal extending additional open-mouthed slot inwhich elastomeric threads can be engaged;

FIGS. 17 and 18 are central longitudinal cross sections of respectivefurther embodiments in which an arch wire attitude controlling springmember to render the bracket active is provided by a flexible extensionof the shutter member;

FIGS. 19 and 20 are central longitudinal cross sections of a furtherembodiment consisting of a convertible lower left first molar tube, theshutter member being respectively in slot open and closed positions,FIG. 20 also showing a specially configured tool for use with thedevices of the invention; and

FIGS. 21 and 22 are similar perspective views from the mesial/labial ofthe convertible molar tube of FIGS. 19 and 20, the shutter member beingrespectively in slot open and closed positions, the figures illustratingthe use of such tubes with an arch wire end stop, and also anothermanner in which a mesial extension of the pivot member pin can be usedto provide anchoring means for auxiliary devices.

DESCRIPTION OF THE INVENTION

Similar parts are given the same reference number in all the Figures ofthe drawings wherever this is appropriate. It may be noted that thedevices shown in FIGS. 1 through 11 are intended to be used attached tothe lingual surfaces of incisor or canine teeth, while those shown inFIGS. 12-14 are intended to be used attached to the lingual surfaces ofbicuspid or molar teeth. FIGS. 19-22 show convertible type orthodontictubes, that in FIGS. 19 and 20 being active, having an attitudecontrolling spring therein. while that in FIGS. 21 and 22 Is passive.

In this specification and the appended claims, for convenience inlanguage the devices and parts thereof are referred to, unless otherwisespecified, as they would be used mounted in the upper arch region of apatient's mouth, especially since the brackets described are intendedprimarily for use in lingual procedures. However, all of the brackets ofthe invention may be used for either labial or lingual procedures. Thelabial and lingual direction designations are reversed between the twoprocedures, e.g. the bracket surface referred to as the labial surfacein the labial procedure becomes the lingual surface in the lingualprocedure, and vice versa, and the arch wire slot usually opens to thelingual and not the labial, although as described above it may insteadopen to the occlusal. Again for convenience in description the devicesare described as having specific named surfaces but, as will beapparent, smooth exterior contours can only be achieved by avoidingsharp edges and sharp edged junctions wherever possible, and the varioussurfaces therefore usually merge smoothly with one another without adefinite junction between them being apparent.

The devices described and shown herein are all intended for use in theso-called straight wire technique with which each bracket is attached toits respective tooth in an attitude such that, as the arch wire attemptsto return to its preformed arch shape and to be straight as seen in amesial-distal, labial-lingual plane, the tooth is moved toward itsdesired optimized position and attitude. In order for the arch wire tobe straight at the conclusion of the procedure the brackets fordifferent teeth must accommodate the very different inclinations of thetooth surfaces to which they are attached. There are two main methods bywhich this is done, either by suitable shaping of the bracket bases andof their base surfaces that contact the teeth surfaces, or by changingthe inclination of the arch wire slots. In the brackets shown herein allof the torque requirements (rotation about a mesial distal axis),angulation requirements (rotation about a labial lingual axis), andfirst order pre-adjustments, are obtained by suitable shaping of thebracket bases, particularly of the surface that engages the toothsurface, and by variation of the base thickness, so that when the teethare in their optimum attitude and rotational position all of the slotsurfaces engaged by the arch wire are aligned. The other method of slotinclination can also be used in the brackets of the invention, eitheralone or in combination with the first-described method. However, whenthe other method is used, with some brackets the inclination of the slotmay be so extreme that, for example, in a bracket fixed to the lingualsurface of a central incisor no attempt is made to have the slot remainparallel with the labial lingual axis and instead, as mentioned above,it opens to the occlusal parallel to the gingival occlusal axis (asviewed from the mesial or distal). Such a configuration allows easierinsertion of the arch wire into the lingually mounted brackets.Nevertheless such devices are within the scope of the language of theappended claims.

Referring now particularly to FIGS. 1 and 2, the bracket device showntherein consists of a bracket body comprising a bracket body memberhaving labial, lingual, gingival, occlusal, mesial and distal surfaceportions 10, 12, 14, 16, 18 and 20 respectively, the orientationdirections being shown in FIG. 1 by corresponding arrows. The bracketbody member has attached to its gingival surface, as for example bylaser welding along its edges, a bracket base 22 consisting of a thinmetal foil, with a layer 24 of metal wire mesh attached to its gingivalsurface, the open pores of the mesh facilitating the cementing of thebracket to a tooth. All of the brackets shown and described herein aremounted on the respective tooth by such cementing, as increasingly ispreferred, although they could also be mounted by the older method ofattaching them to tooth-embracing bands, which method is not illustratedbut is well known to those skilled in the art. The body member isprovided with a mesial-distal extending arch wire receiving slot 26having its lingual side open, the slot in this embodiment being ofrectangular transverse cross section in a gingival-occlusal,labial-lingual plane and having labial, gingival and occlusal surfaces28, 30 and 32 respectively. The slot receives an arch wire 34 (see forexample FIGS. 10, 11, 16 and 17), which usually in the early stages of aprocedure is of circular cross section and of small enough diameter forthe bracket to slide freely along it once the arch wire is fully withinthe slot and fully aligned therein. Subsequently the arch wire usuallyis replaced by one of larger diameter, and thereafter with wires whichalso may instead be of D-shape or rectangular cross section.

Means for retaining the arch wire in the slot, and releasing it whenrequired, consist of a shutter member, indicated generally by arrow 36,that is mounted by a pivot member in a centrally disposed recess 38opening to the labial and occlusal surface portions 10 and 16. In thisembodiment the pivot member consists of a pair of coaxial mesial-distalextending pivot pins 38 that pass through the shutter member and thebracket body, so that the member is movable about a common pivot axis 42of the pins between a slot closed position, as shown in FIGS. 1 and 3,in which the shutter closes the open lingual slot side, and a slot openposition, as shown in FIG. 4, in which the open lingual slot side isunobstructed. The facing ends of the pins are spaced from one another toprovide a space between them whose function will be explained below. Inthis embodiment the pivot member is disposed in the body closer to thelabial end than to the lingual end. The provision of the recess 38 inthe bracket body member results in two parallel wing members 44 withparallel facing mesial and distal walls, the mesial-distal dimensionbetween the two walls being such that the shutter member 36 has justenough clearance, but without any appreciable play, to move freelytherein in its movement between slot open and closed positions. Thepivot pins are of circular cross section and are engaged tightly incorresponding circular cross section bores 46 in the wing members; onceengaged in these bores they are held rigidly against rotation, forexample by laser spot welding their ends to the bracket body by spotwelds 48, as shown in FIGS. 1, 5 and 7. The shutter member consists of apivot portion 50 that is always within the recess 38, and through whichthe pivot pins 38 extend, and a slot closure portion 52, the latterbeing in this embodiment integral with the pivot portion, the shuttermember having been machined from a single block of metal. In thisembodiment the mesial-distal dimension of the slot closure portion isthe same as that of the pivot portion. In the slot closed position ofthe shutter member surface 54 of the slot closure portion buts againstarchwire slot surface 30 to establish the fully closed position, whilesurface 56 closes the open lingual side of the arch wire slot, andsurface 58 registers and aligns with slot surface 32 to form acontinuation of that surface.

The shutter member is retained securely in the slot closed position bythe interaction of latch means comprising cooperating latch membersrespectively with the pivot portion 50 and the pivot member pins 40. Thepivot portion 50 has the form of a hollow cylindrical tube of at leastapproximately annular cross section in a gingival-occlusal plane thatembraces the pivot pins 40, the tube being provided with a mesial-distalextending central bore 60 of diameter such that it is a close fit aroundthe pins, while permitting the required pivoting rotation of the shuttermember thereon. A mesial-distal, gingival-occlusal extending segmentjunction between the pivot and closure portions is indicated in FIG. 2by a broken line 61. The pivot portion is provided close to thisjunction with a mesial-distal extending slot 62 that extends completelythrough its wall, so that the circular segment of the cylindrical tubewall that extends from the slot 62 to the junction 61 is able to move byflexing radially outward away from the pivot pins, such flexing beingaccompanied by a circumferential movement apart of the opposed facingwalls of the slot. This movable segment of the pivot portion is made aslong as possible to provide the maximum amount of flexing, andcorresponding maximum amount of radially inward and outward movement ofthe free end of the segment. In practice the movable segment canconstitute from about 200° to 270° of the total circumference of thepivot portion part wall.

In this embodiment the latch members provided by the latch means consistof mesial distal extending V or U transverse cross section latch groovesor recesses 64 in the surfaces of the pivot pins 40 and a mesial distalextending latch projection 66 of complementary profile immediatelyadjacent to the slot 62 and protruding radially inward from the innerwall of the bore 60. The relative positions of these latch members issuch that in the slot closed position the projection is engaged snuglyand securely in the grooves and positively retains the shutter member inthat position. Movement of the shutter member out of that positionrequires that the movable segment be flexed radially outward against theresilience of the material of the member, and remain thus flexed whilethe shutter member is in any other position. The V or U cross sectionsof the recesses and projection provide a cam action in their engagementand disengagement. Such action is particularly advantageous duringengagement in that as soon as the projection engages the downwardinclined face of the recess the resilience of the movable segmentpositively moves the projection into full engagement in the recess withcorresponding positive movement of the shutter member. Part 68 of themovable segment immediately adjacent to the projection 66 bulgesradially outward, a groove 70 being provided in the inner wall of thepivot portion to maintain uniform wall thickness and to allow a crosssection for the projection that ensures more secure engagement. Thegroove also ensures that there is no abrupt junction of the projectionwith the remainder of the moveable segment. As the shutter memberrotates to move the slot closure portion away from the slot closedposition the bulging part engages the adjacent wall of the base member22, as shown in FIG. 4, thereby acting as a stop member preventingfurther rotation, so that the shutter member is held in a preferred slotopen position in which the opposed closure member surface 52 and slotsurface 30 provide an inwardly tapered opening that will facilitatecapture of an arch wire and guide it into the slot 26.

The slot closure member is relatively easily moved from the slot open toslot closed position by finger pressure and/or by the pressure appliedby a suitable dental tool. Opening is more difficult because of thesmooth, flush outer surfaces and the projection 66 must be sprung fromthe grooves 64. The required opening movement is facilitated by theprovision of a radially extending hole 72 in the centre of the slot 62,so that a dental tool 73 (see FIG. 8), such as a probe, can be insertedinto the hole and used as a lever to rotate the shutter member, while atthe same time assisting in the flexing of the movable segment byspreading the walls of the slot apart. As was described above, the twoseparate pivot pins 40 have their inner facing ends spaced apart, andthe resultant space enables the tool to be inserted sufficiently deeplyfor adequate torque to be applied. The use of two separate pins doesrequire accurate alignment of the two grooves 64 before the anchoringspot welds 46 are applied, and another method is to use a single groovedpivot pin and to drill the hole 72 after the pin is in welded in place,the hole then passing through the wall of the pivot portion and asufficient depth into the pin (see FIG. 16). It will be noted that inslot closed position the occlusal surface of the slot closure portion 52are flush with the corresponding occlusal surface 16 of the bracketbody, and similarly the lingual surfaces of the slot closure portion isflush with the corresponding lingual surface 12 of the bracket body, sothat in such position the bracket presents smooth, solid exteriorsurfaces that minimize the likelihood of rough contact between thebrackets and the tongue and adjacent tissue of the mouth.

The bracket as so far described is “passive”, in that the only controlof tooth movement provided is by the interaction produced by contactbetween the arch wire and the walls of the arch wire slot 26. It ispreferred in most procedures that the brackets be “active”, i.e. thatthey include some inherent means for controlling the attitude of thebracket relative to the arch wire, and to that end each is providedwithin the recess 38 with a thin sheet metal flat attitude controllingspring member. The spring member has a fixed end portion 74 that is heldrigidly in the bracket body, and a free end portion 76 extending intothe arch wire receiving slot for engagement in a mesial-distal,labial-lingual plane with an arch wire in the slot, such engagementurging the arch wire toward the cooperating surfaces of the arch wireslot and the slot closure portion. The spring is of vertical cross shapein plan (St. George orientation) with transversely extending side arms78, and may be inserted in the bracket as it is assembled with the sidearms sandwiched between the bracket body member and the base member 22,recesses 80 being provided in the body member to receive the side arms.Other methods of attachment can be employed such as laser welding orriveting.

The force with which the spring engages an arch wire is dependentprimarily on the dimensions of the spring, particularly its width andthickness, and also upon the cross section dimension of the arch wire.The force can also be adjusted by forming the spring with differentamounts of preloading before the bracket is assembled, for example byadjustment of its profile. A preferred material for the springs andshutter members used in the orthodontic devices of the invention is thefamily of nickel-titanium alloys, commonly referred to as superelasticshape recovery metal alloys, in that they can withstand without damagestrains of as high as about 6-8%, as compared to the usual maximum ofabout 0.5% for stainless steels, the materials most commonly previouslyused. There is now adequate literature available as to the performanceand fabrication of springs using these materials and further explanationis not required herein. Stainless steels of the required qualities willusually continue to be the material of choice for the device body andthe pivot pins.

Referring now particularly to FIGS. 3 and 4, in this embodiment thefunction and operation of the shutter member 36 and its latch means, andof the attitude controlling spring 74-78, are identical to the sameelements in the embodiment of FIGS. 1 and 2. The principal difference isthat the shutter member receiving recess 38 now opens only to the bodyocclusal surface, instead of to both the labial and occlusal surfaces,and the body extends much further toward the labial beyond the pivotpins (or pivot pin if a single pin is used) to provide a solid wedgeshaped body portion 81 that reduces (tapers) in gingival occlusaldimension toward the labial, the labial surface 10 being almostnon-existent. The occlusal surface of this body portion 81 is a smoothextension of the occlusal surface 16 of the remainder of the body. Thearch wire slot 26 still opens to the lingual surface.

Canine and incisor teeth are characterized in that their labial-lingualdimension decreases progressively from the gingival to the occlusal, ascontrasted with bicuspids and molars which are more nearly uniform indimensions in this direction. A common problem encountered inorthodontic treatment is that the patient has a deep-bite malocclusionin which the lower incisors are set too far lingually from the upperincisors for the teeth to meet properly when the jaw is closed, so thatthe bite is deeper than it should be. Brackets of the invention, asillustrated by FIGS. 3 and 4, are particularly suited for use whentreating such a problem in that the gingival-occlusal dimension of thebracket body can readily be made to decrease progressively from thelingual to the labial, and this decrease can be made to correspondapproximately to the average increase in dimension of a canine orincisor tooth. With such a bracket attached to such a lingual surfacethe labial-lingual dimension of the bracket-tooth combination is atleast approximately uniform from the occlusal to the gingival, so thatthe bracket occlusal surface lies in a mesial-distal, labial-lingualextending plane. This, together with the fact that in the slot closedposition the occlusal surface portion of the shutter member 36 is flushwith the occlusal surface portion 16 of the bracket body, means that thebracket is thereby able to provide a combined occlusal surface which isunobstructed and can constitute a bite plane against which the cuttingedge of the respective opposed lower tooth can engage during bitingaction. Once the malocclusion has been corrected the lower incisor nolonger engages the opposed lingual mounted bracket. This structuretherefore has a number of practical advantages. The added labialextension adds structural strength and can with advantage be madesomewhat longer than is shown. The lingual brackets now also function asbite planes to prevent the lower incisors from reaching their usualdeep-bite malocclusion over-closure, and can therefore replace theacrylic bite plates that are placed in the mouth to correct this. Theyalso operate similarly to prevent any interference with the brackets onthe lower teeth while the malocclusion is present, so that they can bebonded to the teeth without fear that they will be detached as a resultof over-biting. It also permits the posterior teeth to be erupted duringthe procedure to further reduce the overbite. Such brackets aredescribed and claimed in my U.S. Pat. No. 6,506,049, issued 14 Jan.,2003, referred to above.

A bracket as illustrated by FIGS. 5 through 8 differs from those ofFIGS. 1 through 4 in that the part of the slot closure portion 52providing the slot closure surface 56 is wider in the mesial-distaldirection than the pivot portion 50, and preferably its width is that ofthe body member, so that its end surfaces 82 are flush with the mesialand distal surfaces 18 and 20 of the body member. The extended slotclosure portion therefore provides mesial and distal extending surfaces84 that are extensions of the surfaces 56, and that are able tocooperate with surfaces 86 on the bracket body wings 44 in providing anadditional restraining force that assists the latch means in retainingthe shutter member in the slot closed position. Thus, the dimensions ofthe bracket body and of the shutter member are such that, as the shuttermember moves about the pivot axis 42 toward the slot closed position,the surfaces 84 at first engage and then rub tightly against thecorresponding surfaces 86 with an interference fit. Owing to their verysmall dimensions there may be a very small amount of flexing of theparts 82 toward the lingual against the elasticity of the material. Oncein the slot closed position the moving interference fit engagementbetween the surfaces becomes a stationary butting interference fitengagement, with the butting sections of the shutter member permanentlyvery slightly flexed lingually outward from the bracket body to providea correspondingly directed retaining force. Owing to this tight rubbingengagement an increased, but entirely acceptable, amount of force isrequired to move the shutter member into the slot closed position untilthe latch means engage, and similarly an increased amount of force isrequired to disengage the latch means and move the shutter member towardthe slot open position. The extended slot closure surfaces also areoperative to provide the bracket with increased rotational controlduring the orthodontic procedure because of the increased length ofmesial distal engagement with the arch wire.

Such a method of adding to the retention the slot closure member in slotclosed position is completely feasible with a product such as anorthodontic bracket in that the number of openings and closings it islikely to experience during its working life is limited, so that thepossibility of wear of the rubbing engaging surfaces is minimal.Orthodontic brackets are already of necessity manufactured to very closetolerances (e.g. 0.00025 mm or 0.0001 in) so that the required jamminginterference fit can easily be achieved. The tiny amount of anydeflection produced in the end portions 82 is highly unlikely to evenapproach the yield point of the material, so that permanent deflectionis correspondingly highly unlikely. In the event that in some bracketsof a batch the amount of this retaining force is considered to beinsufficient this can be corrected by the application of a very thin(e.g. 0.0025 mm or 0.001 in) hard adherent coating to one or both of theengaging jamming surfaces 84 and 86.

FIG. 8 is a perspective view showing brackets of the invention, of thekind illustrated by FIGS. 5 and 6, cemented to the lingual surfaces ofadult upper incisors in order to show the extremely small size that ispossible. For example only, brackets of the invention can readily beproduced having a mesial distal dimension (not including the base 22 ormesh 24) of 1.96 mm (0.077 in) to 2.5 mm (0.098 in), a labial lingualdimension of 1.2 mm (0.048 in), and a gingival occlusal dimension of 1.8mm (0.070 in) to 3.05 mm (0.112 in). Again for example only, in bracketsof such dimensions the pivot pin/s 40 typically will be of diameter inthe range 0.4 mm (0.016 in) to 0.5 mm (0.020 in), preferably 0.45 mm(0.018 in), while the latch groove 64 and the latch projection 66 willbe of radial dimension in the range 0.05 mm (0.002 in) to 0.10 mm (0.004in), preferably 0.062 mm (0.0025 in). The figure also shows a typicaldental tool 73 that can be used in moving the shutter member from closedto open position by inserting it into the hole 72 and rotating it in thedirection of arrow 88. FIG. 9 shows a bracket of the invention attachedto a base 22, and to the same scale a prior art Hanson SPEED system(Trademark) bracket as disclosed for example in my prior U.S. Pat. No.4,492,573, referred to above, the outlines of the two brackets beingsuperimposed in order to demonstrate clearly the difference in theirsizes and the small dimensions to which it is possible to make the newbrackets.

FIGS. 10 and 11 are central longitudinal cross sections through afurther embodiment in which the shutter member 36 is disposed adjacentto the lingual end of the bracket body rather than to the labial end,such a bracket being appropriate for use on the lingual surfaces ofupper incisors and canines. FIG. 10 shows the shutter member in the slotclosed position and with a round cross section arch wire 34 in the slot26. In this embodiment the attitude controlling spring 74-78 issandwiched between the base member 22 and the movable pivot portion 50of the shutter member, the part thereof which buts against the springbeing of uniform radius about the axis 42 until the bulge 70 engages thespring to act as a stop member for the shutter member in slot openposition. This configuration enables the bracket body to be providedtoward its labial end with a mesial distal extending bore 90 that canreceive a supplementary wire, or used as an anchor point for othersupplementary orthodontic devices.

The bracket of FIG. 12 is intended for application to canine and incisorteeth, but the variation in structure which this illustrates is equallyapplicable to those intended for application to molar or bicuspid teeth.The function and operation of the shutter member 36, its latch means,and the attitude controlling spring 74-78, are the same. The structuraldifference is that the disposition of the latch means members, namelythe latch grooves or recesses 64 and the latch projection 66, isreversed. A mesial distal extending recess 64 is provided in the wall ofpivot portion 50, while a cooperating radial outward extendingprojection 66 is provided on the pivot pin or pins 40. The movablesegment of the wall carries the recess 64 as close as possible to itsfree end to provide the maximum length of wall that is flexed radiallyoutward in order to disengage the latch means.

Referring now to FIGS. 13 (sheet 5) and 14 (sheet 7), brackets asillustrated thereby can be attached to the teeth lingual surfaces andcan also be attached to the labial surfaces of all teeth if given theappropriate built in torque and provided with base members 22 (“standoffs”) of appropriate shape and dimensions. Brackets frequently areprovided with attachment means for auxiliary devices consisting of quitelarge external hooks and mushroom headed receptors for anchors andtension devices and, particularly with devices intended for lingualprocedures, these are likely to cause problems owing to their engagementwith the adjacent mouth surfaces and the tongue. Owing to the extremelysmall size of the brackets of the invention it becomes more difficult toprovide such attachment means in a single machining process, and thismay be done in two stages by providing a shallow mesial distal extendingrecess 92 at the junction of the lingual and gingival surface portions,and then soldering or brazing into the slot a short piece 94 of archwire of appropriate cross section of mesial distal length such that itsends protrude beyond the mesial and distal surfaces of the bracket body.FIG. 15 (sheet 9) shows another structure that provides such externalattachment means without the need for any additional process; in thisembodiment the pivot member pin 40 is extended both mesially anddistally beyond the mesial and distal surfaces of the bracket body toprovide the desired hooks. Instead only one of the ends may be extendedin this manner. One or both of the protruding ends may be bent to hookform, as is shown below in FIGS. 21 and 22 in connection with theconvertible tube shown therein.

FIG. 16 shows a further embodiment in which the bracket is provided withmeans that permit ready attachment thereto of an auxiliary element, suchas an elastomeric thread. The bracket body is provided approximately atthe junction of the lingual and gingival surfaces with a mesial distalextending slot 96 having a narrow mesial distal extending mouth 98through which an elastomeric thread 100 can be squeezed. This is done bystretching the thread longitudinally until its cross section has beenreduced from its normal relaxed or somewhat tensed outline, as shown atthe upper left of the Figure, to a much reduced highly stretchedoutline, as shown in the middle of the Figure. Once inside the slot andallowed to return to its normal outline, as shown in the right hand partof the Figure, and as permitted by the cross section shape of the slot,it will frictionally oppose movement of the ribbon through the slot, orcan be knotted or otherwise provided with an enlarged stop member 102 toprevent mesial or distal movement through the slot or escape therefromin those directions. For example, mesial or distal directed tension canbe applied to the bracket by use of a thread provided at regularintervals along its length with stop knots or beads 102 of a size thatcannot pass through the slot. The tension can be adjusted by cutting anappropriate length of the thread and engaging it in the slot with theendmost knot or bead butting against the appropriate mesial or distalsurface.

The bracket of FIG. 17 is intended for use on lower central incisors inlabial procedures, its arch wire slot 26 opening to the labial, whilethe shutter member 36 is pivotally mounted about a pivot axis 42 closerto the gingival end. The device differs in structure from thosedescribed above in that an integral attitude controlling spring memberis constituted by an integral flexible portion 104, 106 of the shuttermember that is an extension of the slot closure portion 52. Thisextension is of recurved cross section in an occlusal, gingival, labial,lingual plane and consists of two somewhat approximately parallel arms104 and 106. The arm 104 is an integral extension of the slot closureportion, while the arm 106 constitutes a spring member free end portionthat in slot closed position extends into the slot for engagement in amesial-distal extending plane with an arch wire 34 in the slot, suchengagement urging the arch wire into engagement with lingual andgingival slot surfaces 29 and 30 respectively. In the slot closedposition the flexible portion of the shutter member, and in thisembodiment more specifically the occlusal facing surface of the arm 104,which is relatively straight, is positively engaged along most of itslength with an inclined gingivally facing surface 108 of the device bodyso as preload the flexible portion and urge the free end portion towardengagement with the arch wire. This inclined surface and preload alsofacilitate the retention of the shutter member in slot closed position,since the spring member must be flexed toward the gingival in order tomove from that position. The flexible portion is of mesial distaldimension to be a close fit within the device body recess 38, so that inslot closed position it is engaged by the mesial and distal facinglateral wall surfaces 110 of the device body, parallel to theocclusal-gingival-labial-lingual plane, to protect it againstdisplacement under mesial or distal directed stresses applied thereto.In this embodiment the cement-receiving layer 24 of metal wire mesh isreplaced with a thin layer of sintered metal powder. Such a structuremakes full use of the much higher strain-tolerant characteristics of thenickel-titanium alloys referred to above, and these are the preferredmaterials for the manufacture of the combined shutter member andattitude controlling spring.

The device of FIG. 18 is for use on upper bicuspids and has its archwire slot opening to the occlusal; otherwise the device functions in thesame manner as that of FIG. 16. The surface 108 which is engaged toprovide preload for the spring member is of much shorter length andengages the arm 106 very close to its junction with the arm 104, thesurface being curved to be of complementary shape. The supportingsurfaces 110 are of much shorter labial-lingual length, but are adequateto protect the spring member against mesial-distal directed forces, eventhough they engage only the curved junction between the two arms. Inboth of the two last described embodiments the latch means constitutedby the latch groove 64 and cooperating latch projection 66 can bereplaced by an equivalent latch means, for example as shown in my priorU.S. Pat. No. 5,224,858, the disclosure of which is incorporated hereinby this reference.

FIGS. 19-21 show the application of the invention to convertible tubeswith which the shutter can be opened to allow insertion of the archwirefrom the buccal, the same references as in the prior Figures being usedfor equivalent parts. Such tubes and are sufficiently long (e.g. about0.16 in or 4 mm) that they can be passive, and usually do not requirethe presence of an attitude controlling spring 74/76, but such a springcan easily be provided as is shown for example in FIG. 19. Such longtubes provide sufficient rotation control while permitting a smallenough occlusal-gingival dimension to prevent occlusal interference.Preferably, as shown, the free edge of the slot closure portion 52engages in a mesial-distal extending recess 111 in the tube body toprovide a smooth exterior surface such that the shutter member cannot besnagged in a manner that might overcome the retention of the latchcausing the shutter to open, FIG. 20 illustrates a particular structurefor the opening tool 73, the end that engages in the opening 72 being areduced diameter nipple.

FIGS. 19 and 21 show that with the shutter in slot open position thearch wire is easily “scooped” into the slot. The use of convertibletubes facilitates the installation of a cable type arch wire 34, asshown in FIGS. 21 and 22. Thus, with the wire accurately in place asplit-tube end stop 112 can be crimped on the wire butting the tube, andthe wire then removed from the tube while the surplus end is severedcleanly without danger to the patient and without leaving frayed endsthat might cause interference with the tongue and mouth tissue. FIGS. 21and 22 also show the provision of anchoring or attachment means forauxiliary devices by extending one or both ends the pivot pin beyond thewing members 44; in addition the protruding ends can easily be bent toform retaining hooks.

List of Reference Signs

-   10. Bracket body labial surface portion    -   12 Bracket body lingual surface portion-   14 Bracket body gingival surface portion-   16 Bracket body occlusal surface portion-   18 Bracket body mesial surface portion-   20 Bracket body distal surface portion-   22 Bracket body base foil-   24 Metal wire mesh-   26 Arch wire receiving slot-   28 Slot labial surface-   29 Slot lingual surface (when slot opens to the occlusal)-   30 Slot gingival surface-   32 Slot occlusal surface-   34 Arch wire-   36 Shutter member-   38 Bracket body recess-   40 Pivot member (pins) for shutter member-   42 Pivot pin pivot axis-   44 Bracket body wing members-   46 Pivot pin receiving bores in wing members 44-   46 Spot welds holding pivot member stationary-   50 Shutter member (36) pivot portion-   52 Shutter member (36) slot closure portion-   54 Slot closure portion surface butting arch wire slot surface 30-   56 Slot closure portion surface closing labial or occlusal side of    arch wire slot-   58 Slot closure portion surface aligning with arch wire slot surface    32-   60 Bore in pivot portion receiving pivot member-   61 Junction between pivot and slot closure portions of shutter    member 36-   62 Through slot in wall of pivot portion 50-   64 Latch grooves in pivot pins 40 or in pivot portion 50-   66 Latch projection on pivot portion 50 or on pivot member 40-   68 Bulged part of movable segment constituting stop member-   70 Groove on opposite wall of bulged part-   72 Radially extending tool receiving hole-   73 Tool for moving shutter member from slot closed position-   74 Fixed end portion of attitude controlling spring-   76 Free end portion of attitude controlling spring-   78 Attitude controlling spring side arms-   80 Recesses in bracket body receiving spring side arms 78-   81 Wedge shaped body part providing extended bite plane-   82 End surfaces of mesial-distal extending slot closure portion-   84 Extended slot closure surfaces of slot closure portion-   86 Surfaces on bracket body wings 44 cooperating with surfaces 84-   88 Arrow showing operative direction of rotation of tool 71-   90 Supplementary mesial distal extending bore in bracket body-   92 Mesial distal extending recess receiving hook forming wire 94-   94 Wire in recess 92 forming external hooks-   96 Mesial distal slot receiving elastomeric ribbons-   98 Narrow mouth of slot 96-   100 Elastomeric thread-   102 Stop bead or knot on elastomeric thread-   104 Arm of recurved spring extension attached to shutter member-   106 Arm of recurved spring extension providing free end-   108 Surface of device body engaged by arm 106 to provide preload-   110 Mesial distal device body surfaces supporting spring extension    104/106-   111 Recess in body receiving shutter member edge-   112 End stop member crimped on to arch wire cable 34

1. An orthodontic device for use with orthodontic arch wires comprising:a device body having labial, lingual, gingival, occlusal, mesial anddistal surface portions, the body having therein a mesial-distalextending arch wire receiving slot having one mesial distal extendingside open to a device body surface portion to permit insertion of anarch wire into the slot and its removal therefrom; a pivot membermounted by the device body and establishing a mesial-distal extendingpivot axis; and a shutter member mounted by the pivot member forpivoting movement about the pivot axis between a slot open position inwhich the open slot side is open, and a slot closed position in whichthe shutter member closes the open slot side to retain an orthodonticarch wire in the slot; wherein the shutter member comprises: a pivotportion mounted by the pivot member for the pivoting movement of theshutter member; a slot closure portion movable with the pivot portion,extending mesially distally with respect to the device body, and in theslot closure position closing the slot open side; and latch means havinglatch means members cooperating with one another and operative betweenthe pivot member and the pivot portion when the shutter member is inslot closed position to retain the shutter member in that position. 2.An orthodontic device as claimed in claim 1, wherein the cooperatinglatch means members comprise a recess in one of the pivot member and thepivot portion, and a projection from the other of the pivot member andthe pivot portion, and wherein with the shutter member in the slotclosed position the recess and the projection are cooperatively engagedwith one another to retain the shutter member in that position.
 3. Anorthodontic device as claimed in claim 1, wherein the pivot member hasat least one end portion thereof extending beyond the mesial or distalsurface portion and constituting attachment means for the attachment tothe device of other orthodontic devices.
 4. An orthodontic device asclaimed in claim 1, wherein In the slot closed position of the shuttermember the mesial and distal ends of the slot closure portion engagewith immediately adjacent surface portions of the device body with aninterference fit engagement between them providing a retaining forcesuch that in addition to the latch means the shutter member is alsoconstrained thereby in the slot closed position against movement out ofthat position, and movement of the shutter member into the slot closedposition requires flexing of the slot closure portion in a directionaway from the device body against the resilience of the material of theslot closure portion.
 5. An orthodontic device as claimed in claim 1,and comprising an attitude controlling spring member within the devicebody having a fixed end portion fixed against movement relative to thedevice body and a free end portion extending into the arch wirereceiving slot for engagement in a mesial-distal extending plane with anarch wire in the slot, such engagement urging the arch wire toward theslot closure part.
 6. An orthodontic device as claimed in claim 5,wherein the attitude controlling spring member is of thin metal sheetwith at least one transversely extending side arm, and is retainedwithin the device body by having one or both of the side arms sandwichedbetween a part of the device body containing the arch wire slot and abase member fastened to the device body.
 7. An orthodontic device asclaimed in claim 1, and comprising an attitude controlling spring memberconstituted by a flexible portion of the shutter member that with theshutter member in slot closed position has a free end portion extendinginto the arch wire receiving slot for engagement in a mesial-distalextending plane with an arch wire in the slot, such engagement urgingthe arch wire into engagement with the respective slot walls
 8. Anorthodontic device as claimed in claim 7, wherein in the slot closedposition the flexible portion of the shutter member is positivelyengaged with a surface of the device body so as preload the flexibleportion and urge the free end portion toward engagement with an archwire in the arch wire slot.
 9. An orthodontic device as claimed in claim7, wherein the flexible portion of the shutter member is of recurvedcross section in an occlusal, gingival, labial, lingual plane, and inslot closed position is engaged by lateral walls of the device bodyparallel to the last-mentioned plane to protect it against mesial ordistal directed stresses applied thereto.
 10. An orthodontic device asclaimed in claim 1, and for application to the lingual surface of anincisor or canine tooth, which teeth are characterized in that theirlabial-lingual dimension decreases progressively from the gingival tothe occlusal; wherein in the slot closed position the occlusal surfaceportion of the shutter member is flush with the occlusal surface portionof the device body to thereby provide a combined occlusal surface whichis unobstructed; and wherein the gingival-occlusal dimension of thedevice body decreases progressively from the labial to the lingual, thedecrease corresponding to the average increase from the occlusal to thegingival of an incisor or canine tooth, so that when the bracket isattached to the lingual surface of an incisor or canine tooth theunobstructed combined occlusal surface provides a labial-lingualextending bite plane surface which a tooth edge of an opposed incisor orcanine tooth can engage during biting action to oppose overbite.
 11. Anorthodontic device as claimed in claim 2, wherein the recess is providedin the pivot member and the projection is provided on the pivot portion.12. An orthodontic device as claimed in claim 11, wherein the shuttermember pivot portion comprises a pivot portion part embracing the pivotmember, the pivot portion part having a mesial distal extending boretherein through which the pivot member extends whereby the pivot portionpart has a wall of at least approximately annular transverse crosssection around the pivot member; the wall having therein a mesial distalextending radial slot from its interior to its exterior so that the wallis discontinuous around the pivot member and has a movable segmentthereof able to move radially toward and away from the pivot member byflexing thereof; and wherein one of the projection and the recess of thelatch means members is carried by the movable segment and moves into andout of engagement with the other of the recess and the projection by theflexing of the movable segment.
 13. An orthodontic device as claimed inclaim 2, wherein In the slot closed position of the shutter member themesial and distal ends of the slot closure portion engage withimmediately adjacent surface portions of the device body with aninterference fit engagement between them providing a retaining force inaddition to the latch means such that the shutter member is alsoconstrained thereby in the slot closed position against movement out ofthat position, and movement of the shutter member into the slot closedposition requires flexing of the slot closure portion in a directionaway from the device body against the resilience of the material of theslot closure portion.
 14. An orthodontic device as claimed in claim 2,and comprising an attitude controlling spring member within the devicebody having a fixed end portion fixed against movement relative to thedevice body and a free end portion extending into the arch wirereceiving slot for engagement in a mesial-distal extending plane with anarch wire in the slot, such engagement urging the arch wire toward theslot closure part.
 15. An orthodontic device as claimed in claim 14,wherein the attitude controlling spring member is of thin metal sheetwith at least one transversely extending side arm, and is retainedwithin the device body by having one or both of the side arms sandwichedbetween a part of the device body containing the arch wire slot and abase member fastened to the device body.
 16. An orthodontic device asclaimed in claim 1, wherein the shutter member pivot portion comprises apivot portion part embracing the pivot member, the pivot portion parthaving a mesial distal extending bore therein through which the pivotmember extends whereby the pivot portion part has a wall of at leastapproximately annular transverse cross section around the pivot member;the wall having therein a mesial distal extending radial slot from itsinterior to its exterior so that the wall is discontinuous around thepivot member and has a movable segment thereof able to move radiallytoward and away from the pivot member by flexing thereof; and whereinone of the latch means members is carried by the movable segment andmoves into and out of engagement with the other of the latch meansmembers by the flexing of the movable segment.
 17. An orthodontic deviceas claimed in claim 16, wherein the movable segment constitutes fromabout 200° to 270° of the total circumference of the pivot portion partwall with the respective latch means member disposed immediatelyadjacent to the radial slot.
 18. An orthodontic device as claimed inclaim 16, wherein the radial slot in the pivot portion part has a toolreceiving aperture therein through which a tool may be inserted by anoperator for flexing of the movable segment to disengage the projectionand recess for movement of the shutter member out of the slot closedposition.
 19. An orthodontic device as claimed in claim 18, wherein thepivot member comprises two separate coaxial pins having their facingends spaced apart to permit insertion of the tool between them.
 20. Anorthodontic device as claimed in claim 16, wherein the movable segmenthas a part thereof adjacent to the location of the respective latchmeans member extending radially outward and engageable with a surface ofthe device body to limit the movement of the shutter member beyond adesired slot open position.
 21. An orthodontic device as claimed inclaim 16, wherein In the slot closed position of the shutter member themesial and distal ends of the slot closure portion engage withimmediately adjacent surface portions of the device body with aninterference fit engagement between them providing a retaining force inaddition to the latch means such that the shutter member is alsoconstrained thereby in the slot closed position against movement out ofthat position, and movement of the shutter member into the slot closedposition requires flexing of the slot closure portion in a directionaway from the device body against the resilience of the material of theslot closure portion.
 22. An orthodontic device as claimed in claim 16,and comprising an attitude controlling spring member within the devicebody having a fixed end portion fixed against movement relative to thedevice body and a free end portion extending into the arch wirereceiving slot for engagement in a mesial-distal extending plane with anarch wire in the slot, such engagement urging the arch wire toward theslot closure part.
 23. An orthodontic device as claimed in claim 22,wherein the attitude controlling spring member is of thin metal sheetwith at least one transversely extending side arm, and is retainedwithin the device body by having one or both of the side arms sandwichedbetween a part of the device body containing the arch wire slot and abase member fastened to the device body.
 24. An orthodontic device foruse with orthodontic arch wires comprising: a device body having labial,lingual, gingival, occlusal, mesial and distal surface portions, thebody having therein a mesial-distal extending arch wire receiving slothaving one mesial distal extending side open to a device body surfaceportion to permit insertion of an arch wire into the slot and itsremoval therefrom; a pivot member mounted by the device body andestablishing a mesial-distal extending pivot axis; and a shutter membermounted by the pivot member for pivoting movement about the pivot axisbetween a slot open position in which the open slot side is open, and aslot closed position in which the shutter member closes the open slotside to retain an orthodontic arch wire in the slot; wherein the shuttermember comprises: a pivot portion mounted by the pivot member for thepivoting movement of the shutter member; a slot closure portion movablewith the pivot portion, extending mesially distally with respect to thedevice body, and in the slot closure position closing the slot openside; and an attitude controlling spring member constituted by aflexible portion of the slot closure portion that with the shuttermember in slot closed position has a free end portion extending into thearch wire receiving slot for engagement in a mesial-distal extendingplane with an arch wire in the slot, such engagement urging the archwire into engagement with the respective slot walls.
 25. An orthodonticdevice as claimed in claim 24, wherein in the slot closed position theflexible portion of the slot closure portion is positively engaged witha surface of the device body so as preload the flexible portion and urgethe free 33end portion toward engagement with an arch wire in the archwire slot.
 26. An orthodontic device as claimed in claim 24, wherein theflexible portion of the slot closure portion is of recurved crosssection in an occlusal, gingival, labial, lingual plane, and in slotclosed position is engaged by lateral walls of the device body parallelto the last-mentioned plane to protect it against mesial or distaldirected stresses applied thereto.
 27. An orthodontic device as claimedin claim 24, and including latch means having latch members cooperatingwith one another and operative between the pivot member and the pivotportion when the shutter member is in slot closed position to retain theshutter member in that position.